This experiment was carried out in a multistratum system in Manaus - Amazonas to study the growth and maturation of annato fruits and seeds (Bixa orellana L.) cultivated in this system. At the stage of maxim blooming about 1.500 flowers were marked. From this stage on, 45 fruits were picked at random once a week until the fruits reached the maturation stage, totalizing 12 collections. A detailed description was made of the fruit development stage in every collection. The fruit and seed dry matter; fruit length and diameters; and seed length, diameter, humidity, viability and vigor were also determined. The annato seed began to germinate at 62 days after anthesis, when they attained 62.5% total dry matter. Regarding seed growth related to dry matter a sigmoid behavior was observed, with three distinct phases, reaching maximum dry matter on the 76th day after anthesis. At this stage, the seeds reached the maximum germination and vigor stage, and the fruits were turning from reddish to yellowish hues and the seeds showed the chalazae with lilac-colored rings and brown funiculum, which characterizes physiological maturation.